1. Field of the Invention
The present invention relates to a printer provided with two print heads and a control method thereof.
2. Description of the Related Art
Currently, a thermal printer is used to print a receipt with a register in a restaurant and a store. Usually single-side printing is done to the receipt, and a large amount of receipt paper is used in the case of printing a large amount of information, resulting in uneconomical increase of cost.
Therefore, sometimes a double-side simultaneous printing thermal printer is used so as to effectively print information on a receipt paper as much as possible. In the thermal printer of such a type, print data is divided into data groups to be printed on front surface and back surface of a thermal paper respectively. Then, printing is carried out simultaneously on the both surfaces of the thermal paper, whereby the data groups are integrated. As an example of the thermal printer of such a type, a thermal printer including two platen rollers and two thermal heads has been proposed (Jpn. Pat. Appln. Laid-Open Publication No. 11-286147).
In such kind of thermal printer, the first platen roller and the second platen roller are rotated at the same speed while being synchronous with each other. The first thermal head carries out the printing on one of the surfaces of the thermal paper by the passage of the thermal paper between the first platen roller and the first thermal head. The second thermal head carries out the printing on the other surface of the thermal paper by the further passage of the thermal recording paper between the second platen roller and the second thermal head.
However, in the thermal printer having the two thermal heads (first and second thermal heads), if there occurs any abnormality in one of the thermal heads, print head error is detected to stop the entire operation of the printer. Thus, the printer cannot perform the subsequent printing until the print head error is eliminated.
In this case, a user needs to contact a serviceman for correction of the print head error. That is, the user cannot use the printer until the print head error is eliminated by the serviceman.